Water-in-Salt Electrolytes for Reversible Zinc Electrodeposition for Dynamic Windows

Abstract

Reversible metal electrodeposition (RME) is an emerging and promising method for designing dynamic windows with electrically controllable transmission, excellent color neutrality, and wide dynamic range. Despite its very negative deposition voltage, Zn is a viable option for metal-based dynamic windows due to its fast switching kinetics and reversibility. In this manuscript, we describe the construction of Zn RME dynamic windows using water-in-salt electrolytes (WISe). By systematically comparing different electrolytes, we study the effects of different WISe components on Zn RME spectroelectrochemistry. This insight allows us to design practical two-electrode 25 cm2 Zn dynamic windows, the first examples of RME devices with WISe. We also establish a link between the morphology of the Zn electrodeposits and the optical contrast of the transparent electrodes during switching. Taken together, these studies highlight a potential design strategy for the construction of RME dynamic windows.